Definition of Temporomandibular disorders:
"Wide spectrum of specific and non specific disorders that
produce symptoms of pain and dysfunction in muscles of mastication,
temporomandibular joint and other associated structures."
Temporomandibular joint
TMJ is a true synovial joint with articular surfaces covered
with fibrocartilage compared to other synovial joints which are covered by a
hyaline cartilage. TMJ has bilateral articulation with a rigid end point of
closure.
Articular
disc
Articular disc is composed of fibrous connective tissue and
which are lack of vessels and nerves (therefore no inlflammation). Articular
disc separates the joint in to two compartments. Disc can be divided in to four
distinct regions. They are: anterior band, intermediate zone, posterior band
and bilaminar region.
Attachments
of the disc
Medially and laterally: Poles of the condyle
Anteriorly: capsular ligament and Lateral pterygoid
Posteriorly: wall of the glenoid fossa, squamotympanic
fissure, posterior surface of the condyle
Capsule
of TMJ
Composed of thin fibrous connective tissue and strongly
reinforced by lateral ligaments
Synovial membrane
Synovial membranes lines the peripheries of upper and lower
joint compartments.
Synovial fluid
Synovial fluid composed of mucopolysaccharides (hyaluronic
acid).Function of Synovial fluid is Nutrition, Lubrication and Clearance.
Muscles
of mastication
- Temporalis
- Masseter
- Medial pterygoid
- Lateral pterigoid
Accessory muscles
- Digastric
- Mylohyoid
- Geniohyoid
Blood
supply to TMJ
Superficial temporal and deep auricular arteries
Innervation
to TMJ
Auriculotemporal nerve.
Epidemiology of temporomandibular disorders
40-75% population has at least one sign of TMD and at least
33% has one symptom of the TMD’s. However overall prevalence of TMD complains
in general population is very small and actually only 3.6%-7%.
Etiology of functional disturbances of TMJ
No single factor is responsible for the TMD’s because of its
tolerance and adaptive capacity. However the insult is much more than the
tolerance symptoms will appear.
Insults can be local or systemic. Generally local events can
be trauma and trauma could be either microtrauma or macrotrauma. Sudden force
which results in structural alteration in the joint are macrotrauma. Any small
forces which act on the joint repeatedly for long time and cause TMD are micro
trauma. Fon example: Bruxism, clenching.
Systemic factors also contribute to TMD’s in a significant proportion,
mainly psychological factors such as anxiety and depression. However non
psychological disorders also can lead to TMD’s. Eg: degenerative, endocrine,
metabolic and neoplastic.
Etiologic theories of Temporomandibular disorders
Mechanical displacement theory
Neuromuscular theory
Muscular theory
Pshycological theory
Phyco-sociological theory
Current understanding about TMD etiology
It is multifactorial which interplay of anatomical,
neuromuscular and psychological result in TMD. TMD passes three major stages in
its disease process. They are predisposition, initiation and perpetuation.
History and Examination of TMD’s
History plays a major role in diagnosis and management of
temporomandibular disorders. It is important to concentrate on presenting
complaint, history of presenting complaint, history of trauma (either micro or
macro trauma) and history of pain if patient present with pain complaint.
Psycological history may also contribute to the diagnosis in significant
proportion.
Examination of TMD’s
Examination of the TMJ should consist of inspection,
palpation and auscultation. Any color change and morphological alteration in
the masticatory should be noted. Particular attention must be paid for mouth
opening and both comfortable and maximum unaided mouth opening should be
measured. Any deviation or deflection in the mouth opening should be noted. One
should not forget to palpate muscles of mastication and neck muscles too. Both
joints should be palpated for tenderness and abnormalities in path of opening.
Joint should be auscultated as abnormal sound as “Click” or “Crepititions” are
felt.
TMJ imaging
Radiological techniques
- Plain radiography
Dental
panoramic tomography
TMJ
views-Transcranial view, Transpharyngeal
view, Transmaxillary
view
- CT scan
- MRI scan
- Arthrography- contrast radiography. Good to asses details of disc position. Can be double or single contrast arthrography
- Arthroscopy
- Bone scan
- Ultrasound scan
Diagnostic classification of temporomandibular
disorders(TMD’s)
02.TMD articular disorders
03.Masticatory muscle disorders
Temporomandibular disorders classification (Anatomical)-by
American association of orofacial pain
Congenital or developmental
disorders
Aplasia-faulty or incomplete development eg: hemifacial
microsomia or first and second branchial arch syndromes
Hypoplasia- incomplete
or underdevelopment. Can be associated with certain syndromes or could be due
to trauma or infection.
Hyperplasia- over development that is non neoplastic
increase in number of normal cells.
Neoplasia
Disc
derangement disorders
Described as abrupt alteration or interference of the disc
condyle structural relation during mandibular movements in opening and closing.
(During translational movements)
Disc displacement with reduction
Disc displacement without reduction
Disc displacement with reduction
Disc is displaced temporarily anterior than normal. When the
mouth is opened displaced disc reduces or improves its structural relationship
with the condyle.
Symptoms
Majority are symptomless. However some may develop pain.
Diagnostic criteria
Reproducible joint noise which occurs usually, at variable
positions during opening and closing the mandibular movements.
Soft tissue imaging revealing anteriorly displaced disc
which improves its position during mouth opening (MRI or Arthrography shows the
joint space in drop shape) and hard tissue imaging without showing any
degenerative changes.
Other diagnostic criteria
Pain if present precipitated by movement
Deviation of the mandible during movement coincide with
click
No restriction of the mandibular movements
Episodic and momentary catching of smooth jaw movements
during mouth opening that self reduces with voluntary mandibular repositioning.
Differential diagnosis
Anatomic variation
Osteoarthritis
Disc displacement without reduction
Disc displacement without reduction is an altered or
misarranged disc condyle relation that is maintained mandibular translation.
Disc is non reducing or permanently displaced and disc position does not
improve with mandibular movement.
Sign and symptoms
No click
Mouth opening restricted.
Marked limitation of the laterotrution of the mouth (towards
the opposite side)
Pain if tries to open the mouth
Jaw deflects to the affected side.
Some patient will achieve normal opening with time.
Diagnostic criteria
Persistant limited mouth opening with history of sudden
onset(Less than 35mm)
Deflection towards the affected side of the mouth.
Marked limitation of the laterotrution of the mouth (towards
the opposite side)
Soft tissue imaging shows the non reducing disc.
Other diagnostic criteria
Pain which increase with forceful mouth opening
History of clicking ceased with locking
Pain on palpation of on the joint
Moderate arthritic changes in hard tissue imaging
Differential diagnosis
Acute syanovitis
Myospasm
TMJ dislocation
The condition which condyle is positioned anterior to the
articular eminence and is unable to return to closed position.
Dislocation manifest clinically as an inability to close the
mouth and duration of dislocation may be momentary or prolonged.
Inflammatory disorders
Capsulitis/Syanovitis
Polyarthritides eg: Rheumatoid arthritis.Gout
Capsulitis and syanovitis
Capsulitis is inflammation capsular ligament
Syanovitis is inflammation of syanovial membrane.
It is impossible to differentiate these two conditions
Symptoms and Signs
Localized TMJ pain that is increased by palpation and during
function
No extensive arthritic changes in hard tissue imaging
May accompany TMJ pain during rest, limited motion of joint,
fluctuation swelling, pain in the ear.
Differential diagnosis
Osteoarthritis
Polyarthritis
Ear infection
Neoplasia
Polyarthritides
Joint inflammation and structural changes caused by and
generalized,systemic polyarthritic condition such as
Rhematoid arthritis
Juvenile Rheumatoid arthritis ( Still’s disease)
Spondyloarthropathies (ankylosing spondylitis, psoriatic
arthritis, infectious arthritis)
Crystal induced diseases(Gout and chondrocalcinosis)
Other connective tissue discorders (Scleraderma,Sjogren’s
disease,SLE)
Diagnostic criteria for polyarthritides
Pain with mandinular function
Point tenderness in palpation
Limited motion
Radiological changes
Sometimes pain at rest
Other joint involvement
Positive serology
Crepetitions with mandibular function
Osteoarthritis
Osteoarthritis is non inflammatory arthritic condition. This
can be primary or secondary.
Primary osteoarthritis
A degenerative condition characterized by deterioration and
abrasion of articular tissue and simultaneous remodeling of the underlying
subchondral bone due to overloading of the remodeling mechanism. No
identifiable systemic and local cause can be found.
Diagnostic criteria
Pain with function
Tenderness over the joint
No identifiable etiology
Joint crepetition
Radiological evidence
Subchondral
sclerosis
Osteophyte
formation
Erosion
Joint
space narrowing
Secondary osteoarthritis
An associate prior event can be identified which overload
the remodeling mechanism. Such possible etiologies are trauma or infection.
Ankylosis
Fracture
Masticatory muscle disorders
Myofacial pain
Myositis
Myospasm
Myofibrotic contracture
Neoplasia
Myofacial pain or trigger point myalgia
Myofacial pain is a pain disorder involving pain referred
from trigger points within myofascial structures, either local or distant from
the pain. Myofacial pain syndromes are common conditions that results from
small hyperplastic trigger points. this pain can be referred from irritable
points or its associated fascia or other locations.
Myofacial trigger points: myofascial trigger points
are local areas of firm hypersensitive bands in a muscle producing pain.
Features of a trigger point
Source of constant deep pain
Autonomic features may be present such as reddening of eyes
Presence of local twitch response
Presence of jump sign
Associated with emotional disturbances
Trigger point can be classified as “Active” or “Latent”
Active trigger points are
Responsible for spontaneous pain
Localized to 2-5mm of hypersensitive areas
Can occur in any muscle of the body but commonly seen in
head, neck and shoulders
Latent trigger points are
Not a cause of clinical complaint of pain
Manual palpation demonstrates pain
Myositis: Inflammation of the muscles
Generally arises due to trauma or infection resulting
limited range of jaw movements. Sometimes ossification may result due to
inflammation (Myositis ossificans)
Diagnostic criteria
Pain usually continuous
Diffuse tenderness over the muscle
Increased pain with mandibular movement
Myospasm
Sudden involuntary tonic contraction of the muscle lead to
shortening of the muscle and therefore limited motion.
Diagnostic criteria
Acute pain at rest with function
Markedly reduced function
Increased EMG activity
Myofibrotic contracture (Muscles undergo fibrosis)
I this condition there will be a pain less shortening of the
muscle. It shows resistance to passive stretch as a result of fibrosis of
tendons, ligaments and muscles. This condition usually doesn’t give pain unless
stretched forcefully.
Diagnostic criteria
Limited motion
Underlying firmness on passive stretch
No pain
Management of TMD,s
Aim of management
Alleviate pain
Restore function
Resumption of normal daily
activities
Management modalities vary
enormously over a great modalities. Therefore selection of the most appropriate
modality is very important.
Treatment modalities
Conservative
Patient education and self care
Rest and relaxation
Cognitive behavioral management
Pharmacotherapy
Occlusal therapy
Orthopedic appliances
Physiotherapy
Rehabilitation of dental deficits
Management of trigger points
Surgical
Arthrocentesis
Arthroscopy
Arthroplasty
Disectomy
Condylectomy
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